solution in search of a problem

[tmbg]

I have an edcor power transformer that I got off ebay once upon a time, and I'm trying to figure out what it might be useful for.

It's an EM0757-120.

Here's how it's labeled:

SEC: Red = 360V 250mA Black/Red=C.T.
Blue=10.9V, 2.5A

I assume they mean 360VCT, or 180-0-180.

10.9V doesn't seem terribly common of a filament voltage, and it's not centertapped so I can't use it as a ~5V secondary.

With the low HT voltage and oddball filament voltage, maybe it would be useful for a phono or linestage, undervolting the heaters on some small signal tubes?

Anyone have any other ideas on something it might be useful for?

[kheper]

You could use the filament winding for a 6.3V tube, if you go with DC.

10.9 / 1.41 = ~7.7Vdc

The diodes should drop 1.4V. If not, you could drop it with a resistor. However, 2.5A is not alot of current. Maybe an SE el84 amp. The 180-0-180 windings should do ~250Vdc.

[EWBrown]

It would work with 11BM8s, 11MS8s or 10GV8s. Filament voltage is within their specs, and 180-0-180 AC would rectify to approx. 240-250VDC B+,
Four of these tubes would consume about 140-150 mA total plate current, and the filaments are 450 mA per tube, 1.8 Amps total. 8K to 10K A-A OPT, Hammond 1608 or 1609 would be a good match for any of these tubes.

/ed B

[tmbg]

Cool! I have one of the tubedepot 10GV8 push pull kits. Maybe I'll pull it apart and use it to build something new.

[DeathRex]

Heres a list of ESRC's $1 tubes at 10 volts: 10AL11 10C8 10DR7 10DX8 10EB8 10HF8 10JA8 10JT8 10JY8 10KR8 10KU8 10LE8 10T8.

You can also filter the DC and get 12 volts.

[TerrySmith]

You can also use 5v tubes connected in series such as two 5HA7 or 5GH8 as driver tubes, and 5V6 pairs, 5AQ5, 5CZ5 etc. Other outputs could be 10GK6 or 10BQ5.

How much current is it rated for?

[kheper]

You can also filter the DC and get 12 volts.

Good one. A FWB with the 10V winding will yield ~12V. Make sure to allow the center tap to float (cut it off or tape it) when using this type of rectifier. The max available DC current will only be ~1.5A, however.

[scott17]

I second the 10GK6. Very close to 6BQ5/EL84. In fact I think it is a 6BQ5 with a different pinout. I used these in a push pull. Sounds great.

[Geek]

In fact I think it is a 6BQ5 with a different pinout.

It is! They are electrically identical.

[dspth]

10EM7

Miniblok
http://www.dogstar.dantimax.dk/tubestuf/index.htm

[Gingertube]

Want to get fancy.

Try some old Western Electric Pentodes to make a preamp
WE310, WE311 etc.
Can often be found quite cheap with STC310A, STC311 etc. numbers. STC were liscenced (by WE) second source manufacturers.
They ae 10V filaments.

Cheers,
Ian